API updated for ICU4J 60.1

API details:
- New DisplayContext value for initializing LocaleDisplayNames
  It's an option to set whether locale display name should fallback to
  use default value when lang data is not available in attribtues, e.g. separator
  See CTS test ULocaleTest.TestDisplayNames for its usage
  Upstream ticket: http://bugs.icu-project.org/trac/ticket/12700
- New method MeasureFormat.getUnitDisplayName to to get unit display names
  CTS: MeasureUnitTest.testDisplayNames
  Upstream ticket: http://bugs.icu-project.org/trac/ticket/12029
- New getters and setters in String type for DecimalFormatSymbols
  Useful when the symbol can't be presented by one 2-byte java char
  Upstream ticket: http://bugs.icu-project.org/trac/ticket/10368
- Expose TimeZone.SystemTimeZoneType values b/65475899
  Existing method TimeZone.getAvailableIDs takes the enum type
  but there was no such value exposed in the Android SDK
- New constants for Unicode 10.0
  Details: http://unicode.org/versions/Unicode10.0.0/
  UScript, UCharacter, UProperty
- New contants in MeasureUnit

Bug: 68208236
Bug: 65475899
Test: m
Test: m update-api
Change-Id: I116b0e6f5a3ffb0820ed3802f7e063f9c052dd53